ZA200605618B - Finished lubricants comprising lubricating base oil with high monocycloparaffins and low multicycloparaffins - Google Patents

Description

FINISHE D LUBRICANTS COMPRISING LUBRICATING B#ASE OIL

WITH HIGH MONOCYCLOPARAFFINS

AND LOW MULTICYCLOPARAFFINS

FIELD OF THE INVENTION

The invention relates to a process for manufacturing a finishmed lubricant with the ste=ps of a) performing a Fischer-Tropsch synthesis ©n syngas to provide a product stream; b) isolating from said product stream a substantiall=y paraffinic wax feed having less than about 3 O ppm total combined mnitrogen and sulfur, and less than about 1 wt%s oxygen; C) dewaxing ssaid substantially paraffinic wax feed by hydroissomerization dewaxing Lasing a shape selective intermediate pore size mo lecular sieve with a noble metal hydrogenation component wherein the hydroisomerization temperature is between about 600°F «(315°C) and about 75°F (399°C), whereby an isomerized oil is peroduced; d) hydrofinish ing said isomerized oil, whereby a lubricating base oil is produced having: a low weight percent of all molecules with at least one aromatic fuanction, a high weight percent of all molecules witha at least one cycloparaffin function, and a high ratio of weight percent «of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins; and e) blending the lubricating base oil with at least one lubricant additive.

The invent._ion also relates to the composition and use of the fi nished lubricants gproduced by the process disclosed herein. The proocess manufactu res finished lubricants with excellent oxidation stability, low wear, high viscosity index, low volatility, good low temperature properties, and good aadditive solubility and good elastomer compatibility _ The finished lubricants meet the specifications for a wide variety o=f finished lubricants, including multigrade engine oils and automatic trarismission fluids.

BACKGROUND OF THE INVENTION

Finished lubricants aand greases used for various applications, including automobiles, diese! eengines, natural gas engines, axles, transmmissions, and industrial applications consist of two general components, lubricating base oil and additivexs. Lubricating base oil is the major constituent in these finished lubricants and contributes significantly to the properties of the finished lubricarat. In general, a few lubricating base oils &are used to manufacture a wide variety of finished lubricants by varying the mixtures of individual lubricatineg base oils and individual additives.

Numerous govemimg organizations, including original equipnent manufacturers (OE M's), the American Petroleum Institute (AEP),

Association des Consructeurs d’ Automobiles (ACEA), the Amnmerican

Society of Testing and Materials (ASTM), the Society of Automotive

Engineers (SAE), and National Lubricating Grease Institute &NLGI) among others, define the specifications for lubricating base oils and finished lubricants. Increas ingly, the specifications for finished lubricants are calling for products with excellent low temperature properties, high oxidation stability, low volati lity, and good additive solubility and elastomer compatibility. Currently only a small fraction of the base oils manufactured today are able to rmeet the demanding specifications of prermium lubricant products.

Finished lubricants comprising highly saturated lubricating base oils in the prior art have either had very low levels of cycloparaffins; o-r when cycloparaffins we=re present, a significant amount of the cycloparaffins were multicyclopaaraffins. A certain amount of cycloparaffirs are desired in lubricating base oils and finished lubricants to provide addi.tive solubility and elastomer compatibility. Multicycloparaffins are less d esired than monocycloparaff ins, because they decrease viscosity index, lower oxidation stabilitwy, and increase Noack volatility.

Examples of highly saturated lubricating base oils having very low levels of cycloparaffins are polyalphaolefins and GTL base oils made from Fischer-

Tropsch processes such as described in EPA1114124, EPA1114127,

EPA1114131, EPA776959, EPA668342, and EPA1 029029. Lubricating base oils in the prior art with high cyclopaaraffins made from Fischer-

Tropsch wax (GTL base oils) have been described in WO 02/064710. The examples of the base oils in WO 02/064710 had very low pour points, between 10 and 40 weight percent cyclosparaffins, and the ratio of monocycloparaffins to multicycloparaffinus was less than 15. The viscosity indexes of the lubricating base oils in W=Q 02/064710 were below 140.

The Noack volatilities were between 6 aund 14 weight percent. The lubricating base oils in WO 02/064710 vevere heavily dewaxed to achieve low pour points, which would produce readuced yields compared to oils that were not as heavily dewaxed.

The wax feed used to make the base ofils in WO 02/064710 had a weight ratio of compounds having at least 60 ©r more carbon atoms and compounds having at least 30 carbon atoms greater than 0.20. These wax feeds are not as plentiful as feeds with lower weight ratios of compounds having at least 60 or more carbon ators and compounds having at least 30 carbon atoms. The process in WO 02/0647 10 required an initial hydrocracking/hydroisomerizing of the wax feed, followed by a substantial pour reducing step. Lubricating base oil yield losses occurred at each of these two steps. To demonstrate this, in example 1 of WO 02/064710 the conversion of compounds boiling abowe 370°C to compounds boiling below 370°C was 55 wt% in the hydro: cracking/hydroisomerization step alone. The subsequent pour reducinga step would reduce the yield of products boiling above 370°C further. Compounds boiling below 370°C (700°F) are typically not recovered as lubricating base oils due to their low viscosity. Because of the yield lossess due to high conversions the process requires feeds with a high ratio of compounds having at least 60 or more carbon atoms and compounds havings at least 30 carbon atoms.

Finished lubricants containing GTL base oils with high weight percents of all molecules with at least one cycloparaffin function made from Fischer-

Tropsch wax are described in WO ۩2/064711 and WO 02/070636. Both of these applications use the base oil=s taught in WO 02/064710, which are not optimal in that they have a ratio of monocycioparaffins to multicycloparaffins less than 15, viscosity indexes less than 140, and may have aromatics contents greater than 0.30 weight percent. WO 02/064711 teaches a OW-XX grade engine oik and WO 02/070636 teaches an automatic transmission fluid. The OW-XX grade engine oil of Example 3 in

WO 02/064711 is made with a lub-ricating base oil having a ratio of monocycloparaffins to multicyclop-araffins of 13, a viscosity index of 125, and it contains a fairly high level of viscosity index improver, 10.56 weight percent. The automatic transmission fluid of Example 6 in WO 02/070636 is made with a lubricating base oi | having 0.8 weight percent aromatics and a viscosity index of 122.

Due to their high saturates content and low levels of cycloparaffins, lubricating base oils made from rmost F ischer-Tropsch processes or polyalphaolefins may exhibit poo 1 additive solubility. Additives used to make finished lubricants typically have polar functionality; therefore, they may be insoluble or only slightly soluble in the lubricating base oil. To address the problem of poor additive solubility in highly saturated lubricating base oils with low levels of cycloparaffins, various co-solvents, such as synthetic esters, are currently used. However, these synthetic esters are very expensive, and thus, the finished lubricants blended with the lubricating base oils containiing synthetic esters (which have acceptable additive solubility) are also expensive. The high price of these finished lubricants limits the cur rent use of highly saturated lubricating base oils with low levels of cycloparaffins to specialized and small markets.

It has been taught in US Patent Application 20030088133 that blends of lubricating base oils composed of 1) alkylated cycloparaffins with 2) highly paraffinic Fischer-Tropsch derived Lubricating base oils improves the additive solubility of the highly paraffinic Fischer-Tropsch derived lubricating base oils. The lubricating base oils composed of alkylated cycloparaffins used in the blends of this application are very likely to also contain high levels of aromatics (greater than 30 weight percent), such that the resulting blends with Fischer-T ropsch derived lubricating base oils will contain aromatics at levels greater than 0.30 weight percent. The high level of aromatics will cause reducsed viscosity index and oxidation stability.

What is desired are finished lubricants; comprising lubricating base oils with very low amounts of aromatics, high amounts of monocycloparaffins, and little or no multicycloparaffins , that have a moderately low pour point such that they may be produced i n high yield and provide good additive solubility and elastomer compatibwility. Finished lubricants with these qualities that aiso have excellent oxidation stability, low wear, high viscosity index, low volatility, and good low temperature properties are also desired. The finished lubricants should meet the specifications for a wide variety of modem lubricant specifications, including multigrade engine oils and automatic transmission fluids. The present invention provides these finished lubricants and the proce ss to make them.

SUMMARY _OF THE INVENTION

The present invention is directed to a process for manufacturing a finished lubricant with the steps of: a) pe rforming a Fischer-Tropsch synthesis on syngas to provide a product stream, b) isolating from said product stream a substantially paraffinic wax feed having less than about 30 ppm total combined nitrogen and sulfur, aand less than about 1 wt% oxygen; C) dewaxing said substantially paraffinic wax feed by hydroisomerization dewaxing using a shape selective intermediate pore size molecular sieve with a noble metal hydrogenation component wherein the hydroisomerization temperature is between about 600°F (315°C) and about 750°F (399°C), whereby an issomerized oil is produced; d) hydrofinishing said isomerized oil, whereby a lubricating base oil is produced having: a weight percent «of all molecules with at least one aromatic function less than 0.30, a “weight percent of all molecules with at least one cycloparaffin function gre=ater than 10, and a ratio of weight percent molecules containing monocycloparaffins to weight percent molecules containing multicyclopar-affins greater than 15; and e) blending the lubricating base oil with at leask one lubricant additive.

The present invention is also directed to a process for manufacturing a finished lubricant with the steps of: a) performing a Fischer-Tropsch synthesis on syngas to provide a peroduct stream; b) isolating from said product stream a substantially paraffinic wax feed having less than about 30 ppm total combined nitrogen ard sulfur, and less than about 1 wt% oxygen; c) dewaxing said substantially paraffinic wax feed by hydroisomerization dewaxing using a shape selective intermediate pore size molecular sieve with a noble metal hydrogenation component wherein the hydroisomerization teamperature is between about 600°F (315°C) and about 750°F (399°C). whereby an isomerized oil is produced; d) hydrofinishing said isomerized oil, whereby a lubricating base oil is produced having: a weight percen t of all molecules with at least one aromatic function less than 0.30, a weight percent of all molecules with at {east one cycloparaffin function greater than the kinematic viscosity at 100°C in cSt multiplied by three, aand a ratio of weight percent molecules containing monocycloparaffins to “weight percent molecules containing multicycloparaffins greater than 15; and e) blending the lubricating base oil with at least one lubricant additives.

The present invention is also dire«cted to a composition of finished lubricant which comprises a lubricating basse oil having a weight percent of all molecules with at least one aromaatic function less than 0.30, a weight ‘ percent of all molecules with at le=ast one cycloparaffin function greater than 10, and a ratio of weight percent molecules containing monocycloparaffins to weight percent molecules containing multicycloparaffins greater than 15; and at least one lubricant additive. IM addition, the present invention is directed to a composition of finished lubricant which comprises a lubricating base oil having a weight percent ©f all molecules with at least one aromatic function less than 0.30, a weight percent of all molecules with at le ast one cycloparaffin function greater than the kinematic viscosity at 100°C in cSt multiplied by three, and a ratio of weight percent molecules containing monocycloparaffins to weight percent molecules containing musiticycloparaffins greater than 15; and at least one lubricant additive.

The present invention is also directed to a finished lubricant made by the process comprising the steps of: a) performing a Fischer-Tropsch synthesis on syngas to provide a product stream; b) isolating from said product stream a substantially p araffinic wax feed having less than about 30 ppm total combined nitrogen and sulfur, and less than about 1 wt% oxygen; c¢) dewaxing said substantially paraffinic wax feed by hydroisomerization dewaxing using a shape selective intermediate pores size molecular sieve with a noble metal hydrogenation component wherein the hydroisomerization temperature is between about 600°F (315°C) and about 750°F (399°C), whereby an isomerized oil is produced; d) hydrofinishing said isomerized oil, whereby a lubricating base oil is produced, and e) blending the | ubricating base oil with at least one lubricant additive.

The present invention is also d irected to the use of a finished lubricant comprising: a) a lubricating basse oil having a weight percent of all molecules with at least one aromatic function less than 0.30, a weight percent of all molecules with at least one cycloparaffin function greater than 10, and a ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater tha n 15, and b) a least one lubricant additi-ve;

as an engine oil, an automatic transmission fluid, a heavy duty transmission fluid, a power steering fluid, or an industrial gear oil. in another embodiment the pres ent invention is directed to the use of a finished lubricant comprising: a) a lubricating base oil having a weight percent of all molecules with =at least one aromatic function less than 0.30, a weight percent of all molecules with at least one cycloparaffin function greater than the kinematic viscosity at 100°C in cSt multiplied by three, and a ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater than 15, and b) a least one lubricant additive; as an engine oil, an automatic transmission fiuid, a heavy duty transmission fluid, a power steering fluid, or an industrial gear oil.

Using the process of the invention, finished lubricants are prepared which have excellent oxidation stability, fow wear, high viscosity index, low volatility, good low tempera-ture properties, good additive solubility, and good elastomer compatibility. The finished lubricants of the present invention may be used in a wide variety of applications and include, for example, automatic transmission fluids and multigrade engine oils.

Because the lubricating ba se oils have excellent additive stability and elastomer compatibility, finished lubricants may be formulated with little or no ester co-solvent. Becawse the lubricating base oils have such high viscosity indexes finished Bubricants may be formulated using them with little or no viscosity index i mprover. In preferred embodiments the finished lubricants will produce low levels of wear, and will require lower amounts of antiwear additives.

The very low weight percent of all molecules with at least one aromatic function in the lubricating base oil used to make the finished lubricant of this invention provides excellent oxidation stability and high viscosity index. The high weight p ercent of all molecules with at least one cycloparaffin function prosvides improved additive solubility and elastomer compatibility to the lubricating base oil, and to the finished lubricant comprising it. The very high ratio of weight percent of moiecuies containing monocyclopa raffins to weight percent of molecules contaiming multicycloparaffins (or high monocycloparaffins and little to no multicycloparaffins) optirmizes the composition of the cycloparaffins im the lubricating base oil and finished lubricant. Multicycloparaffins are less desired as they dramatically reduce the viscosity index, oxidation stability, and Noack volatility.

BRIEE DESCRIPTION OF THE DRAWING

FIGURE 1 illustrates the plot of Kinematic Viscosity at 100 °C in cSt vs.

Pour Point in degrees Celsius / Kinematic Viscosity at 100 °CS in cSt providing the equation for calculation of the Base Qil Pour Factor:

Base Oil Pour Factor = 7.35 x Ln(Kinematic Viscosity at 100 °C) -18, wherein Ln(Kinematic Viscosity at 100 °C) is the natural logarit hm with base “e” of Kinematic Viscosity at 100 °C in cSt.

DETAILED DESCRIPTION OF THE INVENTION

Finished lubricants comprise a lubricant base oil and at least one axdditive.

Lubricant base oils are the most important component of finished lubricants, generally comprising greater than 70% of the finished jubricants. Finished lubricants may be used in automobiles, diese= engines, axles, transrmissions, and industrial applications. Finished lubricants must meet the specifications for their intended applicati-on as defined by the concerned goveming organization.

Additives which may be blended with the lubricant base oil of the present invention, to provide a finished lubricant composition, include those which are intended to improve select properties of the finished lubricant. Typical additives include, for example, anti-wear additives, EP agents, deztergents, dispersants, antioxidants, pour point depressants, viscosity index improvers, viscosity modifiers, friction modifiers, demulsifiers, antifoaming agents, corrosion inhibitors, rust inhibitors, seal swell agents, emulsifiers, wetting agents, lubricity improovers, metal deactivators, gelling agents, tackiness agents, bactericide=s, fluid-loss additives, colorants, and the like.

Typically, the total amount off additives in the finished lubricant will be approximately 0.1 to about 350 weight percent of the finished lubricant.

However, since the lubricatirmg base oils of the present invention have excellent properties includinag excellent oxidation stability, low wear, high viscosity index, low volatility , good low temperature properties, good additive solubility, and good elastomer compatibility, a lower amount of additives may be required to meet the specifications for the finished lubricant than is typically required with base oils made by other processes.

The use of additives in formulating finished lubricants is well documented in the literature and well known to those of skill in the art.

Finished lubricants contain@ing lubricating base oils with very low aromatic content made prior to this invention have either been formulated with lubricating base oils with very low cycloparaffin content, or with lubricating base oils that had high cycBloparaffin content with considerable levels of multicycloparaffins and/or wery low pour points. The highest known ratio of monocycloparaffins to multticycloparaffins in lubricating base oils containing greater than 10 weight percent cycloparaffins and low aromatics content prior to ®his invention; was 13:1. The lubricating base oil with this high ratio was -the base oil Example 3 from WO 02/064710.

The pour point of this exarmple base oil was extremely low, 45°C, indicating that it was sevewely dewaxed. Severe dewaxing of base oils to low pour points are made ata significant yield disadvantage compared to lubricating base oils dewa xed to more moderate pour points. This base oil only had a viscosity index of 125. This base oil was used in a OW-30 engine oil, Example 3 in VVO 02/064711.

Lubricatimg base oils and finished lubricants containirg high weight percents of all molecules with at least one cycloparafffin function are desired a_s cycloparaffins impart additive solubility amad elastomer compatibility to these products. Lubricating base oilss containing very high ratios of weight percent of molecules containing mormocycloparaffins to weight pearcent of molecules containing multicyclopamraffins (or high monocyc:loparaffins and little to no multicycloparaffins) are also desired as the multicycloparaffins reduce oxidation stability, lower viscosity index, and increase Noack volatility. Models of the effects of m ulticycloparaffins are given in W.J. Gatto, etal, “The Influence of Chemical Structure on the

Physical Properties and Antioxidant Response of Hywdrocracked Base

Stocks ax nd Polyalphaolefins,” J. Synthetic Lubrication 19-1, April 2002, pp 3-18.

By virtues of the present invention, finished lubricantss are made which have excellent oxidation stability, low wear, high viscosity™ index, low volatility, good lovw temperature properties, good additive solubility, and good elastomer compatibility. These finished lubricants mmay be obtained using a process comprising the steps of: a) performing a Fisscher-Tropsch synthesis on syngas to provide a product stream; b>) isolating from said product stream a substantially paraffinic wax feed h aving less than about 30 ppm total combined nitrogen and sulfur, and lesss than about 1 wt% oxygen; c) dewaxing said substantially paraffinic waax feed by hydroisomerization dewaxing using a shape selectiwe intermediate pore size moWecular sieve with a noble metal hydrogenation component wherein the hydroisomerization temperature is betvaseen about 600°F (315°C) and about 750°F (399°C), whereby an isormnerized oil is produced; d) hydrofinishing said isomerized oil, whereby a lubericating base oil is produced having: a weight percent of all molecules with at least one aromati«c function less than 0.30, a weight percent Of all molecules with at least ore cycloparaffin function greater than 10, aned a high ratio of weight percent of molecules containing monocycloparaffin s to weight percent of molecules containing multicycloparaffins (greater than 15); and e) blending the lubricating base oil with at least one lubricant additive.

Alternatively, step d) of the above process may be changed to: d) hydrofinishing said isomerized oil, whereby a lubricating base oil is produced having: a weight percent of all molecules with at least one aromatic function less than 0.30, a weight percent of all molecules with at least one cycloparaffin function greater than the kinematic viscosity at 100°C in cSt smultiplied by three, and a ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater than 15.

Kinematic viscosity is a measurement of the resistance to flow of a fluid under gravity . Many lubricating base oils, finished lubricants made from them, and the correct operation of equipment depends upon the appropriate viscosity of the fluid being used. Kinematic viscosity is determined by ASTM D 445-01. The results are reported in centistokes (cSt). The ki nematic viscosities of the lubricating base oils of this invention are between about 2 cSt and about 20 cSt, preferably between about 2 cSt and about 12 cSt.

Pour point is a measurement of the temperature at which the sample will begin to flows under carefully controlled conditions. Pour point may be determined as described in ASTM D 5950-02. The results are reported in degrees Celsius. Many commercial jubricating base oils have specificatiorss for pour point. When lubricant base oils have low pour points, they also are likely to have other good low temperature properties, such as low cloud point, low cold filter plugging point, low Brookfield viscosity, arad low temperature cranking viscosity. Cloud point is a measureme nt complementary to the pour point, and is expressed as a temperature at which a sample of the lubricant base oil begins to develop a haze under carefully specified conditions. Cloud point may be determined by, for example, ASTM D 5773-95. Lubricating base oils havin g pour-cloud point spreads below about 35°C are also desirable.

Higher pour-cloud point spreads require processirg the lubricating base oil to ve vy low pour points in order to meet cloud poirit specifications. The pour—cloud point spreads of the lubricating base oils of this invention are generally less than about 35°C, preferably less thuan about 25°C, more preferably less than about 10°C. The cloud point_s are generally in the range of +30 to -30°C.

Noa ck volatility of engine oil, as measured by TGA Noack and similar methods, has been found to correlate with oil comnsumption in passenger car -engines. Strict requirements for low volatilityw are important aspects of several recent engine oil specifications, such as. for example, ACEA A-3 and B-3 in Europe, and SAE J300-01 and ILSACC GF-3 in North America.

Any new lubricating base oil developed for use i n automotive engine oils shaauld have a Noack volatility no greater than cmurrent conventional Group or Group |i Light Neutral oils. The Noack volati-lity of the lubricating base oils of this invention are very low, generally lesss than an amount calculated by the equation:

Noack Volatility, Wt%= 1000 x (Kinematic V iscosity at 100°C)%7. In preferred embodiments the Noack volatility is less than an amount calculated by the equation:

Noack Volatility, Wt% = 900 x (Kinematic Vascosity at 100°Cy2%,

Noack volatility is defined as the mass of ail, exxpressed in weight percent, which is lost when the oil is heated at 250 degwrees C and 20 mmHg (2.67 kPa; 26.7 mbar) below atmospheric in a test crucible through which a constant flow of air is drawn for 60 minutes (ASSTM D 5800). A more convenient method for calculating Noack volatility and one which correlates well with ASTM D-5800 is by using a thermo gravimetric analyzer test (TGA) by ASTM D-6375-99. TGAA Noack volatility is used throughout this disclosure uniess otherwise st-ated.

The finished lubmricants of this invention may be blended with other base oils to improve or modify their properties (e.g., viscosity index, oxidation stability, pour point, sulfur content, traction coefficient, or Noack volatility ).

Examples of ba se oils that may be blended with the {lubricating base oils of this invention are conventional Group | base oils, conventional Group |! base oils, conveentional Group Ill base oils, other GTL base oils, isomerized peteoleum wax, polyalphaolefins, polyintemalolefins, oligomerized oflefins from Fischer-Tropsch derived feed, diesters, polyol esters, phosphate esters, alkylated aromatics, alkylated cycloparaffins, and mixtures thereof.

Wax Feed:

The wax feed used to make the lubricating base oil of this invention is substantially paraffinic with less than about 30 ppm total combined nitrogen and sulfur. The level of oxygen is less than about 1 weight percent, preferably less than 0.6 weight percent, more preferably less than 0.2 weight pe=rcent. . In most cases, the level of oxygen in the substantially paraffinic wax feed will be between 0.01 and 0.90 weigh percent. The oil content of the feed is less than 10 weight percent as determined by ASTM D 721. Substantially paraffinic for the purpose =of this inventior is defined as having greater than about 75 mass percert normal paraffin by gas chromatographic analysis by ASTM D 5442.

Nitrogen Determination: Nitrogen is measured by melting the substaantially paraffinic waax feed prior to oxidative combustion and chemiluminesc=ence detection by ASTM D 4629-96. The test method is further described in US 6,503,956, incorporated herein in its entirety.

Sulfur Dete rmination: Sulfur is measured by melting the substantial ly paraffinic wrax feed prior to ultraviolet fluorescence by ASTM 5453-00.

The test method is further described in US 6,503,956.

Oxygen Determination: €xygen is measured by neutron activation analysis according to AS-TM E385-90(2002).

The wax feed useful in thnis invention has a significant fraction with & boiling point greater thar 650°F. The T90 boiling points of the wax feed by ASTM D 6352 are preferably between 660°F and 1200°F, more preferably between 900 °F and 1200°F, most preferably between 1000°F and 1200°F. T90 refer=s to the temperature at which 90 weight percent of the feed has a lower boiling point.

The wax feed preferably has a weight ratio of molecules of at leas® 60 carbons to molecules of at least 30 carbons less than 0.18. The weeight ratio of molecules of at: least 60 carbons to molecules of at least 340 carbons is determined by: 1) measuring the boiling point distributieon of the

Fischer-Tropsch wax boy simulated distillation using ASTM D 6352; 2) converting the boiling gpoints to percent weight distribution by carbon number, using the boilling points of n-paraffins published in Table 1 of

ASTM D 6352-98; 3) summing the weight percents of products of carbon number 30 or greater; 4) summing the weight percents of products of carbon number 60 or -greater; 5) dividing the sum of weight perce=nts of products of carbon nuamber 60 or greater by the sum of weight percents of products of carbon number 30 or greater. Other preferred embosdiments of this invention use Fischer-Tropsch wax having a weight ratio of rmolecules having at least 60 carbons to molecules having at least 30 carbamns less than 0.15, or less than 0.10.

The boiling range distribution of the wax feed useful in the proce=ss of this invention may vary considerably. For example the difference b etween the

T90 and T10 boiling points, determined by ASTM D 6352, may be greater than 95°C, greater than 160°C, greater than 200°C, or even gre=ater than 225°C.

Fischer-Tropsch Synthesis and Fischer-Tropsch Wax

The wax feed for this process is preferably Fischer-Tropsch wax produced from Fischer-Tropsch synthesis. During Fischer-Tropsch synthesis liquid and gaseous hydrocarbons are formed by contacting a synthesis gas (syrmgas) comprising a mixture of hydrogen and carbon monoxicle with a

Fischer-Tropsch catalyst under suitable temperature and pressure reactive con ditions. The Fischer-Tropsch reaction is typically conducted at temperatures of from about 300 degrees to about 700 degrees F (about 150 degrees to about 370 degrees C) preferably from about 40 OQ degrees to about 550 degrees F (about 205 degrees to about 230 degrezes C); pre ssures of from about 10 to about 600 psia, (0.7 to 41 bars) goreferably 30 to 300 psia, (2 to 21 bars) and catalyst space velocities of from about 100 to about 10,000 cc/g/hr., preferably 300 to 3,000 ccig/hr.

Thee products from the Fischer-Tropsch synthesis may range from C4 to

Cae plus hydrocarbons, with a majority in the Cs-C1go plus range. Fischer-

Tropsch synthesis may be viewed as a polymerization reactior. Applying po lymerization kinetics, a simple one parameter equation can describe the en tire product distribution, referred to as the Anderson-Shultz—Flory (ASF) distribution:

Ww, =(l-a) xnxa®'

W here W, is the weight fraction of product with carbon numbe=r n, and a is the ASF chain growth probability. The higher the value of —, the longer th e average chain length. The ASF chain growth probability Of the Czo+ fraction of the Fischer-Tropsch wax of this invention is between about 0.85 ard about 0.915.

T he Fischer-Tropsch reaction can be conducted in a variety Of reactor tyspes, such as, for example, fixed bed reactors containing on.e or more catalyst beds, slurry reactors, fluidized bed reactors, or a conmbination of d ifferent types of reactors. Such reaction processes and reaectors are well k nown and documented in the literature. The slurry Fischer-E ropsch process, whaich is preferred in the practice of the invention, Litilizes superior heat (and nmass) transfer characteristics for the strongly exosthermic synthesis reaction and is able to produce relatively high mo lecular weight, paraffinic hwdrocarbons when using a cobalt catalyst. inthe slurry process, a ssyngas comprising a mixture of hydrogen and carbon monoxide is bubbled wp as a third phase through a slurry which comprises a particulate Fischer-Tropsch type hydrocarbon synthesis catalyst dispersed and susperded in a slurry liquid comprising hydrocarbon pwoducts of the synthesis reaction which are liquid under the reaction cond itions. The mole ratio «of the hydrogen to the carbon monoxide may broadly range from about 0.5 to about 4, but is more typically within the range of from about 0.7 £o about 2.75 and preferably from about 0.7 to akoout 2.5. A particularly preferred Fischer-Tropsch process is taught in EP0609079, also comp letely incorporated herein by reference for all pu rposes.

Suitable Fischer-Tropsch catalysts comprise one or more Group VII catalytic metals such as Fe, Ni, Co, Ru and Re, with cobalit being preferred. Additionally, a suitable catalyst may contain a [oromoter. Thus, a preferre-d Fischer-Tropsch catalyst comprises effective &amounts of cobalt and one or more of Re, Ru, Pt, Fe, Ni, Th, Zr, Hf, U,MgandlLaona suitable imorganic support material, preferably one which ecomprises one or more refractory metal oxides. In general, the amount of cobalt present in the cataly=st is between about 1 and about 50 weight perceent of the total catalyst c omposition. The catalysts can also contain basic oxide promoterss such as ThO, La,03, MgO, and TiOz, promoters such as ZrO,, noble me tals (Pt, Pd, Ru, Rh, Os, Ir), coinage metals (Cu , Ag, Au), and other tramsition metals such as Fe, Mn, Ni, and Re. Suitable support materials- include alumina, silica, magnesia and titania, ow mixtures thereof.

Preferred supports for cobalt containing catalysts comprisse titania. Useful catalysts and their preparation are known and illustrated in U.S. Patent 4,568,66 3, which is intended to be illustrative but non-limaiting relative to catalyst selection.

Hiydroisomerization Dewaxing

According to the present invention, the substantially paraffinic wax feed is clewaxed by hydroisomerization dewaxing at conditions s ufficient to produce lubricating base oil with a desired composition of cycloparaffins znd a moderate pour point. In general, conditions for hydroisomerization dewaxing in the present invention are controlled such thaxt the conversion «of the compounds boiling above about 700 °F in the wax feed to compounds boiling below about 700 °F is maintained between about 10 wt o and 50 wt%, preferably between 15 wt% and 45 wt%.

Hydroisomerization dewaxing is intended to improve thes cold flow properties of a lubricating base oil by the selective addit@ion of branching into the molecular structure. Hydroisomerization dewaxing ideally will achieve high conversion levels of waxy feed to non-waxy iso-paraffins while at the same time minimizing the conversion by cracking.

Hydroisomerization is conducted using a shape selective intermediate pore size molecular sieve. Hydroisomerization catalysts useful in the present invention comprise a shape selective intermediate pore size molecular sieve and a catalytically active metal hydrogenation component on a refractory oxide support. The phrase “intermediate pore size,” as used herein means a crystallographic free diameter in “the range of from about 3.9 to about 7.1 Angstrom when the porous inoreganic oxide is in the calcined form. The shape selective intermediate pore size molecular sieves used in the practice of the present invention are generally 1-D 10-, 11- or 12-ring molecular sieves. The most preferred molecular sieves of the invention are of the 1-D 10-ring variety, where 10-Cor 11-or 12-) ring molecular sieves have 10 (or 11 or 12) tetrahedrally-coordinated atoms (T-atoms) joined by oxygens. Inthe 1-D molecular sieve, the 10-ring (or larger) pores are parallel with each other, and do not @nterconnect. Note, however, that 1-D 10-ring molecular sieves which meet the broader : definition of the intermediate pore size molecular siev e but include intersecting pores having 8-membered rings may also be encompassed within the definition of the molecular sieve of the pressent invention. The classification of intrazeolite channels as 1-D, 2-D and 3-D is set forth by R.

M1. Barrer in Zeolites, Science and Technology, edited by F. R. Rodrigues,

L.D. Roliman and C. Naccache, NATO AS! Series, 1 984 which classification is incorporated in its entirety by refererace (see particularly

Page 75).

Preferred shape selective intermediate pore size molecular sieves used for

Fydroisomerization dewaxing are based upon alumi num phosphates, such 2s SAPO-11, SAPO-31, and SAPO-41. SAPO-11 amd SAPO-31 are more preferred, with SAPO-11 being most preferred. SM-3 isa particularly preferred shape selective intermediate pore size SAPO, which has a crystalline structure falling within that of the SAPO-"11 molecular sieves. ~The preparation of SM-3 and its unique characteristics are described in 16 ®U.S. Patent Nos. 4,943,424 and 5,158,665. Also preferred shape selective intermediate pore size molecular sieves used for hydroisomerization dewaxing are zeolites, such as ZSM-22, ZSM-23, ZSM-35, ZSM-48,

ZSM-57, SSZ-32, offretite, and ferrierite. SSZ-32 aand ZSM-23 are more preferred.

A preferred intermediate pore size molecular sieve is characterized by selected crystallographic free diameters of the chamnels, selected crystallite size (corresponding to selected channel length), and selected acidity. Desirable crystallographic free diameters of the channels of the molecular sieves are in the range of from about 3.9 to about 7.1 Angstrom, having a maximum crystallographic free diameter of not more than 7.1 and a minimum crystallographic free diameter of not less than 3.9 Angstrom.

Preferably the maximum crystallographic free diameter is not more than 7.1 and the minimum crystallographic free diameter is not less than 4.0

Angstrom. Most preferably the maximum crystallosgraphic free diameter is not more than 6.5 and the minimum crystallographic free diameter is not less than 4.0 Angstrom. The crystallographic free «diameters of the channels of molecular sieves are published in the “Atlas of Zeolite

Framework Types”, Fifth Revised Edition, 2001 , by Ch. Baerlocher, W.M.

Meier, and D.H. Olson, Eisevier, pp 10-15, which is incorporated herein by reference.

If the crystallographic free diameters of the channels of a molecular sieve are unknown, the effective pore size of the mo lecular sieve can be measured using standard adsorption techniques and hydrocarbonaceous compounds of known minimum kinetic diameters. See Breck, Zeolite

Molecular Sieves, 1974 (especially Chapter 8); Anderson et al. J. Catalysis 58, 114 (1979); and U.S. Pat. No. 4,440,871, &he pertinent portions of which are incorporated herein by reference. Ir performing adsorption measurements to determine pore size, standard techniques are used. ltis convenient to consider a particular molecule as excluded if does not reach at least 95% of its equilibrium adsorption valu e on the molecular sieve in less than about 10 minutes (p/p0=0.5;25°C). Intermediate pore size molecular sieves will typically admit molecules having kinetic diameters of 5.3 to 6.5 Angstrom with little hindrance.

Preferred hydroisomerization dewaxing catalysts useful in the present invention have sufficient acidity so that 0.5 grams thereof when positioned in a tube reactor converts at least 50% of hexadecane at 370°C, pressure of 1200 psig, a hydrogen flow of 160 ml/min, and a feed rate of 1 mi/hr.

The catalyst also exhibits isomerization selectivity of 40 percent or greater (isomerization selectivity is determined as fo flows: 100 x (weight % branched Cis in product)/(weight % branched Css in product + weight %

Cs in product) when used under conditions leading to 96% conversion of normal hexadecane (n-Cs) to other species-.

Hydroisomerization dewaxing catalysts useful in the present invention comprise a catalytically active hydrogenatio n noble metal. The presence of a catalytically active hydrogenation metal le ads to product improvement, especially viscosity index and stability. The= noble metals platinum and palladium are especially preferred, with platinum most especially preferred. If platinum and/or palladium is used, the total amount of active hydrogenation metal is typically in the range= of 0.1 to 5 weight percent of the total catalyst, usually from 0.1 to 2 weight percent, and not to exceed 10 weight percent.

The refractory oxide support may be selected from those oxide supports which are conventionally used for catalysts , including silica, alumina, silica-alumina, magnesia, titania, and combinations thereof.

The conditions for hydroisomerization dewaxing depend on the feed used, the catalyst used, whether or not the catalyst is sulfided, the desired yield, and the desired properties of the lubricant base oil. Conditions under which the hydroisomerization process of the current invention may be carried out include temperatures from about 600°F to about 750°F (315°C to about 399°C), preferably about 600°F to about 700°F (315°C to about 371°C); and pressures from about 15 to 3000 psig, preferably 100 to 2500 psig. The hydroisomerization dewaxing pwessures in this context refer to the hydrogen partial pressure within the hwydroisomerization reactor, although the hydrogen partial pressure is substantially the same (or nearly the same) as the total pressure. The liquid hourly space velocity during contacting is generally from about 0.1 to 20 hr-1, preferably from about 0.1 to about 5 hr-1. The hydrogen to hydrocarbon ratio falls within a range from about 1.0 to about 50 moles Hz per gmole hydrocarbon, more preferably from about 10 to about 20 moles H; per mole hydrocarbon.

Suitable conditions for performing hydroissomerization are described in

U.S. Patent Nos. 5,282,958 and 5,135,638, the contents of which are incorporated by reference in their entirety.

Hydrogen is present in the reaction zone during the hydroisomerization dewaxing process, typically in a hydroge n to feed ratio from about 0.5to 30 MSCF/bbl (thousand standard cubic feet per barrel), preferably from about 1 to about 10 MSCF/bbl. Generally, hydrogen will be separated from the product and recycled to the reaction zone.

V&V 0 2005/066314 PCT/US2004/038849

Hydrotreating and Hydrofinishing

Hydrotreating refers to a catalytic processs, usually carried out in the presence of free hydrogen, in which the primary purpose is the removal of various metal contaminants, such as arsenic, aluminum, and cobalt; heteroatoms, such as sulfur and nitrogen, oxygenates; or aromatics from the feed stock. Generally, in hydrotreating operations cracking of the hydrocarbon molecules, i.e., breaking the larger hydrocarbon molecules “10 into smaller hydrocarbon molecules, is minimized, and the unsaturated hydrocarbons are either fully or partially hydrogenated. Waxy feed to the process of this invention is preferably hydrotreated prior to hydroisomerization dewaxing.

Catalysts used in carrying out hydrotresating operations are well known in the art. See for example U.S. Patent Nos. 4,347,121 and 4,810,357, the contents of which are hereby incorporated by reference in their entirety, for general descriptions of hydrotreating, hydrocracking, and of typical catalysts used in each of the processes. Suitable catalysts include noble metals from Group VIIA (according to the 1975 rules of the International

Union of Pure and Applied Chemistry”), such as platinum or palladium on an alumina or siliceous matrix, and Garoup VIII and Group VIB, such as nickel-molybdenum or nickel-tin on a n alumina or siliceous matrix. U.S.

Patent No. 3,852,207 describes a su itable noble metal catalyst and mild conditions. Other suitable catalysts aare described, for example, in U.S.

Patent Nos. 4,157,294 and 3,804,51 3. The non-noble hydrogenation metals, such as nickel-molybdenum,, are usually present in the final catalyst composition as oxides, but are usually employed in their reduced or sulfided forms when such sulfide compounds are readily formed from the particular metal involved. Preferwed non-noble metal catalyst compositions contain in excess of a bout 5 weight percent, preferably about 5 to about 40 weight percent molybedenum and/or tungsten, and at least about 0.5, and generally about 1 to about 15 weight percent of nickel and/or cobalt determined as the corresponding oxides. Catalysts containing noble metals, such as platinum, contain in excess of 0.01 percent metal, preferably between 0.1 and 1.0 percent metal.

Combinations of noble metals may also be used, such as mixtures of platinum and palladium.

Typical hydrotreating conditions vary over = wide range. In general, the overall LHSV is about 0.25 to 2.0, preferatoly about 0.5t0 1.5. The hydrogen partial pressure is greater than 2200 psia, preferably ranging from about 500 psia to about 2000 psia. Hydro=gen recirculation rates are typically greater than 50 SCF/Bbl, and are. preferably between 1000 and 5000 SCF/Bbl. Temperatures in the reactor will range from about 300 degrees F to about 750 degrees F (about 150 degrees C to about 400 degrees C), preferably ranging from 450 degrees F to 725 degrees F (230 degrees C to 385 degrees C).

Hydrotreating is used as a step following hydroisomerization dewaxing in the lubricant base oil manufacturing proceess of this invention. This step, herein called hydrofinishing, is intended t-o improve the oxidation stability,

UV stability, and appearance of the product by removing traces of aromatics, olefins, color bodies, and solv-ents. As used in this disclosure, the term UV stability refers to the stabilitw of the lubricating base oil or the finished lubricant when exposed to UV light and oxygen. Instability is indicated when a visible precipitate formss, usually seen as floc or cloudiness, or a darker color develops ugpon exposure to ultraviolet light and air. A general description of hydrofirishing may be found in U.S.

Patent Nos. 3,852,207 and 4,673,487. Clay treating to remove these impurities is an alternative final process step.

Fractionation:

Optionally, the process of this invention may include fractionating of the substantially paraffinic wax feed prior to hydroisomerization dewaxing, or

Claims (8)

WHAT IS CLAIMED |S:

1. A process for manufacturing a finished lubricant, comprising the steps of:

a. perfo rming a Fischer-Tropsch synthesis on syngas to provide a product stream;

b. isolating from said product stream a substantially paraffinic wax feed having less than about 30 ppm total combine d nitrogen and sulfu r, and less than about 1 weight percent oxygen;

c. dewaxing said substantially paraffinic wax feed by= hydr«oisomerization dewaxing using a shape selec=tive intermediate pore= size molecular sieve comprising a noble metal hydrogenation com ponent, wherein the hydroisomerization temp erature is between about 600°F (315°C) and about 750°F (399°C), w=hereby an isomerized oil is produced;

d. hydrofinishing said isomerized oil, whereby a lubricating base oil is produced having:

i. a weight percent of all molecules with at le=ast one aromatic function less than 0.30;

i. a weight percent of all molecules with at le2ast one cycloparaffin function greater than 10; i ii. and a ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater thar 15; and e. blemding the lubricating base oil with at least one= lubricant additive.

2. The proce=ss of claim 1, wherein said substantially paraffinic wax feed has a weight ratio of molecules having at least 60 or more czarbon atoms and moleculess having at least 30 carbon atoms less than 0..18, and a T90 boiling po int between 660°F (349°C) and 1200°F (649°-C).

3. The process of claim 1, wherein said finished lubricant has less than 1 weight pe=rcent ester co-solvent.

4. The process of claim 1, wherein said finished lui bricant has less than 8 weight percent viscosity index improver.

5. The process of claim 1, wherein the finished lutoricant meets the specifications of one of the SAE J300 June 201 viscosity grades for multigrade engine oils: OW-XX, 5W-XX, 10W-X_X, and 15W-XX, where XX is 20, 30, 40, 50, or 60.

6. The process of claim 1, wherein the finished luTbricant meets the requirements of one or more of the following attomatic transmission fluid specifications: DEXRON® li, DEXRON® IIE, DDEXRON® lI|(G), 2003 DEXRON® Ii, MERCON®, MERCON® V, MCOPAR® ATF PLUS, ATF+2, ATF+3, ATF+4, and DEX-CVT®.

7. The process of claim 1, wherein said finished lubricant meets the requirements for one or more of the following Heavy duty transmission fluid specifications: Allison C-4, Allison TES-295, C=aterpillar TO-4, ZF TE-ML 14B, and Voith G607.

8. The process of claim 1, wherein said finished lubricant meets the requirements for one or more of the following power steering fluid specifications: DaimlerChrysler MS5931, Fored ESW-M2C128-C, GM 9985010, Navistar TMS 6810, and Volkswagen TL-VW-570-26.

9. The process of claim 1, further comprising ble=nding the lubricating base oil with an additional base oil selected from the croup consisting of conventional Group | base oils, conventional Group || base oils, conventional Group ll base oils, other GTL baase oils, isomerized petroleum wax, polyalphaolefins, polyinternalsolefins, oligomerized olefins from Fischer-Tropsch derived feed, diesters, polyol esters, phosphate esters, alkylated aromatics, alkylated cyclopamraffins, and mixtures thereof.

10. The process of claim 1, wherein said finished lubricant has an HFRR wear volume with 1 Kg load less than 500,000 cub-ic microns.

11. The process of claim 1, wherein the lubricatirg base oil has a ratio of pour point in degrees Celsius to kinematic viscosity at 100°C in cSt greater than the Base O-il Pour Factor as calculated by the following equation: Base Oil Pour Facto r = 7.35 x Ln(Kinematic Viscosity at 100°C) -18.

12.A finished Lubricant comprising:

a. a luboricating base oil made from Fischer-Tropsch wax, having:

i. a weight percent of all molecules w ith at least one aromatic function less than 0.30;

#ii. a weight percent of all molecules with at least one cycloparaffin function greater than 10;

iii. a ratio of weight percent of molecules containing monocycloparaffins to weight percesnt of molecules containing multicycloparaffins greamter than 15; and b. at lseast one lubricant additive.

13. The finished lubricant of claim 12, wherein the | ubricating base oil has a weight pe recent of all molecules with at least one= aromatic function less than 0.05

14. The finiskned lubricant of claim 12, wherein the Bubricating base oil has a weight pe=rcent of all molecules with at least one cycloparaffin function greater trman 20.

15. The finished lubricant of claim 12, wherein the Imubricating base oil has a ratio of pour point in degrees Celsius to kinematic viscosity at 100°C in cSt greater than the Base Oil Pour Factor as calcul ated by the following equation= Base Oil Pour Factor = 7.35 x Ln(Kirmematic Viscosity at 100°C)

-18.

16. The finislhed lubricant of claim 12, wherein the amount of the lubricating base oil L.s between 10 and 99.9 weight percentt and the amount of lubricant additive is between 0.1 and 30 weigh® percent.

17.The finis hed lubricant of claim 12, having less ®han 1 weight percent ester co-solve nt.

18. The finiss hed lubricant of claim 12, having less —than 8 weight percent viscosity= index improver.

19. The finished lubricant of claim 12 that is compatible2 with one or more elastomers selected from the group consisting of neeoprene, nitrile, hydrogenated nitrile, polyacrylate, ethylene-acrylic, silicone, chlor- sulfonated polyethylene, ethylene-propylene copolymers, epichlorhydrin, fluorocarbon, perfluoroether, and PTFE.

20. The finished lubricant of claim 12, wherein it meetss the specifications of one of the SAE J300 June 2001 viscosity grades for multigrade engine oils: OW-XX, BW-XX, 10W-XX, and 15W-XX, where XX is 20, 30, 40, 50, or 60.

21.The finished lubricant of claim 12, wherein it meets=s the requirements of one or more of the following automatic transmission fluid specifications: DEXRON® Il, DEXRON® IIE, DEXRON® 111(G), 22003 DEXRON® in, MERCON®, MERCON® V, MOPAR® ATF PLUS , ATF+2, ATF+3, ATF+4, and DEX-CVT®. 1% 22.The finished lubricant of claim 12, wherein it meets the requirements for one or more of the following heavy duty transmission fluid specifications: Allison C-4, Allison TES-295, Caterpillar TO4, ZF TE-ML 14B, and Voith G607.

23. The finished lubricant of claim 12, wherein it mee=ts the requirements for one or more of the following power steering fluid specifications: DaimlerChrysler MS5931, Ford ESW-M2C128-C , GM 9985010, Navistar TMS 6810, and Volkswagen TL-VW-570-26.

24. The finished lubricant of claim 12, further comprising an additional base oil selected from the group consisting of convention al Group | base oils, conventional Group ll base oils, conventional Greoup li base oils, other GTL base oils, isomerized petroleum wax, polyall phaolefins, polyinternalolefins, oligomerized olefins from Fis cher-Tropsch derived feed, diesters, polyol esters, phosphate esters, alkylated aromatics, alkylated cycloparaffins, and mixtures thereof. =3) 25.The finished lubricant of claim 12, having an HF "RR wear volume with 1 Kg load less than 500,000 cubic microns.

i

265. The finished lubricant of claim 12, having & Brookfield viscosity at -40°C of : less than 20,000 cP. 2-7 The finished lubricant of claim 26, having a Brookfield viscosity at 40°C of less than 5,000 cP.

2 8.A finished lubricant made by the process comprising the steps of:

a. performing a Fischer-Tropsch synthaesis on syngas to provide a product stream;

b. isolating from said product stream & substantially paraffinic wax feed having less than about 30 ppran total combined nitrogen and sulfur, and less than about 1 weight percent oxygen;

c. dewaxing said substantially paraffinic wax feed by hydroisomerization dewaxing using a shape selective intermediate pore size molecular sieve comprising a noble metal hydrogenation component, wherein the hydroisoreerization temperature is between about 600°F (315°C) and about 750°F (399°C), whereby an isomerized oil is produced;

d. hydrofinishing said isomerized ail, whereby a lubricating base oil is produced having:

i. a weight percent of all molecules with at least one aromatic function less than 0.30;

ii. a weight percent of all molexcules with at least one cycloparaffin function greater than 10; and iii. a ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater than 15; and e. blending the lubricating base oil vith at least one lubricant additive.

29. The use of a finished lubricant comprisi ng:

a. a lubricating base oil made from Fischer-Tropsch wax, having:

i. a weight percent of all mokecules with at least one aromatic function less than 0.30;

i. a weight percent of all molecules with at least one cycloparaffin function greater than 10;

66 . J